I have a Sony burner and I'm using the firmware version 1.0 and have had no problems burning more then 71 minutes, my last oversized disk was 79 minutes. The problem might not be in the firmware but possibly in the software you might be using? Just a thought!!
Sony Supressa 100 e/x2 USB
Sony CD Extreme software
Nero
Clone CD
Padeus
CDrwin